The present invention relates to automatic method and apparatus for packing long stockings or the like, and more particularly relates to improvement in a system for packing, in an automatic fashion, a pair of stockings or the like into a plastic film envelope without use of any cardboard insert.
Although the following description is focussed upon application of the present invention to packing of long stockings, it should be understood that the present invention is advantageously applied to packing of any elongated, substantially flat and easily foldable objects.
Packing of a pair of long stockings in general includes two major steps. In the first step, the stockings are folded into three or more superimposed layers along fold lines perpendicular to their longitudinal direction in order to assume a position suited for insertion into a plastic film envelope. Next, the stockings in the folded state are enclosed into the envelope via its open mouth and the mouth is closed by sealing the flap of the envelope.
In one typical conventional system for folding a pair of stockings, a cardboard insert is first placed on the center section of the stockings and the thigh and calf sections are folded about the cardboard insert one on the other. Next the folded stockings with the inside cardboard insert are wrapped with a cover paper and inserted into a plastic film envelope whose mouth is thereafter closed by sealing its flap. The cardboard insert is used in order to prevent formation of creases on the stockings due to movement of the stockings within the envelope after packing. The cover paper is used for protection and/or decoration purposes.
When such folding of stockings is to be carried out in an automatic fashion, use of those cardboard insert and cover paper necessitates use of an extremely complicated equipment and such a complicated construction cannot always assure rapid and reliable operation of the equipment. Further use of such a cardboard insert and cover paper increases production costs.
In order to enclose the stockings, the mouth of a plastic film envelope is first opened and a pair of folded stockings are inserted into the bag section of the envelope via the open mouth. After the stockings have been inserted, a bonding tape is attached to the flap which is then folded over the bag section for sealing. This process also includes complicated operations. In order to carry out this process in automatic fashion, many different types of automatic equipment have been proposed.
One typical example of such a proposal is the automatic stockings encloser disclosed in Japanese Patent Publication Sho. 50-22477. In the case of this prior art, a pair of upper and lower clampers are used to hold a pair of stockings folded about a cardboard insert and the clampers are moved, by means of a carrier member, towards an envelope placed in a prescribed enclosing station. In this stand-by position, the flap of the envelope is pressed against the bottom face of an operation table by means of a pressor, the upper sheet of its bag section lifted by means of a pneumatic suction nozzle in order to open its mouth, and the mouth is maintained open by operation of a pair of openers actable on the mouth of the envelope. Under this condition, the above-described clampers carrying the stockings enter the bag section of the envelope. Then a solenoid operated pressor presses the envelope downwards against the top face of the operation table and the clampers recede outwards from the envelope while leaving the stockings with the cardboard insert inside the bag section of the envelope. The envelope is discharged outside the equipment by delivery rollers and the flap is folded and sealed by fusion bonding.
In the case of this prior art equipment, the openers are required to act on the envelope in order to keep its mouth open every time an envelope is brought to the enclosing station by the carrier.
In operation, the pair of openers move sideways apart from each other and engage with both lateral ends of the mouth of the envelope in order to keep it open during the enclosing operation. With this construction, it is not feasible to return the openers to their initial position just after complete insertion of the stockings in order to prepare for the next cycle operation since presence of the inserted stockings in the bag section of the envelope hinders smooth movement of the openers.
To avoid this problem, the clampers at the insertion advances towards the delivery rollers in a direction perpendicular to the movement of the carrier and removes the envelope off the openers in engagement with its mouth. After the envelope is removed, the openers return to their initial position in order to prepare for the next cycle operation.
In the case of the above-described prior art equipment, individual envelopes are separately supplied to the enclosing station and, after complete insertion of stockings, separately discharged therefrom. Thus, individual envelopes containing stockings are separately subjected to display on market. When stockings of different sizes, colors or designs are displayed together each in such a separated state, it is often troublesome for buyers to locate ones that they wish to buy since envelopes of different stockings are mixed together in piles. In order to avoid this problem, envelopes of similar stockings should be collected together for display and different stockings should be displayed at different places. This grouped display system, however, requires a large floor space for sales, in particular at super-markets where sales usually span huge members of articles including stockings.
In order to eliminate these disadvantages, it has recently been proposed to combine a number of envelopes of similar stockings together in a side by side relationship to form a band of envelopes. More specifically, a number of envelopes of similar stockings are connected to each other along their sides via aligned pin holes formed at borders between adjacent envelopes so that individual envelopes can readily be separated from the band of envelopes by tearing the band along pin hole lines. A tab with a hook may be attached to one longitudinal end of a band of envelopes so that the band of envelopes can be hung on a diaplay bar. When such a band is employed, there is no danger of mixing of envelopes of different stockings and buyers can easily locate stockings that they wish to buy. By suspending such bands the space necessary for display of many stockings is reduced. In addition, handling of stockings during transportation and storage can be simplified greatly since stockings of similar type are collected together in a common band by envelopes. Length of the band of envelopes can readily be adjusted by producers, dealers and retailers depending on the condition of transportation, storage and display for sales. At markets, buyers can take as many envelopes as desired from the envelopes bands merely by tearing the band along any pin hole line.
In order to suffice this recent demand for the band type sales of stockings, it is now required for stockings producers to ship their product in the form of band of envelopes.
As has been described, in the case of the conventional automatic stockings encloser, individual envelopes in a separate state are intermittently supplied to the enclosing station and, after complete insertion of a pair of stockings, each envelope is discharged off the enclosing station in a direction normal to the line of supply of the envelopes in order to cause disengagement of the openers from the mouth of the envelope. This process of disengaging the opener is feasible since individual envelopes are processed through the enclosing station in a completely separated state. In order to enable band type shipment of stockings, stockings have to be supplied to and discharged from the enclosing station in the form of a band of envelopes. As a consequence, it is no longer feasible to move individual envelopes in a direction normal to the line of supply of the stockings for disengagement for the openers since they are united monolithically in a common band. This means that the conventional mouth opening system for envelopes can no longer be employed in the case of the band type shipment of stockings.
In addition to the foregoing, use of the conventional envelope mouth openers has a further disadvantage that engagement of the openers with lateral ends of the envelope mouth often causes breakage of the ends.